Why use it
If the alternator stops charging, the car keeps running on the battery until voltage falls far enough that the ignition and injectors start misbehaving. A battery light gives you warning while there's still time to get somewhere safe. On a Nexus, you can drive that light from the ECU based on the voltage it measures.
Settings
| Setting | What it does | Our advice |
|---|---|---|
| Output Mode: Digital - Switched | Drives the light from an ECU output, typically a DPO | Use this for a conventional dash bulb or LED |
| Output Mode: CAN Output | Turns on a battery warning on a CAN-connected device, where supported | Use this for a CAN dash or display |
| On Voltage | The light comes on when battery voltage drops below this | Set it below normal charging voltage but above where the engine starts to suffer, then confirm with the engine running and the alternator unplugged |
| Battery Light Output | The wire that drives the light, usually a DPO or a stepper output | Check the output's current rating against your bulb |
Make sure the ECU's measured voltage matches a multimeter at the battery before you trust the threshold. See Battery Voltage, and pair this with Alternator Control if the ECU runs your alternator. More options are under Vehicle Functions.
